# What are the "Wurtz" and "Kolbe" reactions?

Mar 21, 2017

The $\text{Wurtz reaction}$ is simply radical coupling; the $\text{Kolbe reaction}$ is simply carboxylation of phenoxide.............

#### Explanation:

As far as I know (and I am happy to be corrected), neither reaction is particularly useful in the laboratory:

$\text{Wurtz reaction:}$

$2 R - X + 2 N a \rightarrow \left[2 R \cdot + 2 N a X\right] \rightarrow R - R + 2 N a X$

Clearly, the reaction is thermodynamically downhill, but rather unselective.

$\text{Kolbe Reaction:}$

${C}_{6} {H}_{5} O H + 2 N a O H \stackrel{\text{CO"_2"/} \Delta}{\rightarrow} 1 , 2 - {C}_{6} {H}_{4} C {O}_{2}^{-} N {a}^{+} \left(O H\right)$

This uses very high carbon dioxide pressures, and the eventual products, substituted hydroxy benzoic acids are used in aspirin synthesis.